M1 External Monitor Issues

May. 22, 2022



Since moving to an M1 Mac, I’ve noticed some issues with my second screen that I do not experience with my previous Intel Mac or with my current work laptop, which is a Dell Intel PC running Windows 10.

I get a lot of flickering on the screen, which is intolerable if I have Pro-motion and True Tone turned on. Note that these are options for the main display rather than the external monitor. I think this means that Apple does not or cannot let you apply these settings granularly, they have to be on or off system-wide.

Even when these settings are off, there is still a slight flicker on my external monitor. The effect is stronger for darker apps, which is a problem for me as I am a big fan of dark mode. I wouldn’t be happy to switch to lighter themes without resolving the issue, as I wouldn’t want the issue there, latently waiting to strike, when I decide to play a game or edit a dark photo.

The effect is strong enough that I don’t feel able to use the external monitor plugged into the Mac for long periods. This naturally has an impact on my work, as I prefer to work with the fastest machine available to me. Long form writing is easier in my Mac apps—all my muscle memory is in those keyboard shortcuts. I’d love to use R installed to my work machine, but because of the way the world is, we’re left running it through some crappy virtual machine. (More autonomy over a corporate Windows machine is a terrifying prospect, akin to asking for the entire Necronomicon just for a couple of spells.)

I must say that I can’t fault the way macOS handles windows with respect to the second monitor. The window arrangement features are intuitive and I’ve even been able to use Universal Control effectively with this setup. The effect is purely visual and cannot be reproduced on the other two computers I’ve mentioned. Even with this issue, using an external monitor on macOS is much better than on Windows, at least for short periods of time.

The monitor is an HP V28 4K. Perhaps it’s not sufficiently advanced. At the best of times, it’s good not great, but the fact is I’d expect that a more expensive computer should make it look better rather than worse. I have a USB-C 4K adaptor to help my work PC run the screen at 4K, but even that doesn’t help. I think it makes the problem slightly worse, though it does reassure me that the completely unnecessary HDMI port isn’t defective.

Some people on forums with similar issues have given a DisplayPort to USB-C adaptor a try and had decent results. One of those would certainly be cheaper than the new Apple Studio Display, the existence of which is why I suspect that legacy monitors are not well served by M1 hardware. I don’t have the funds for a fancy external display. In fact, I feel lucky to own a second screen at all (Thanks Black Friday!).

At WWDC next month, I really hope that the next iteration of macOS will be a Snow Leopard style sweep through some of the bugs that are holding back the Mac. I think support of legacy devices fits Apple’s green credentials and it would help me save up for that Studio Display. After all, if I wanted to use a flickering display with poor driver support, Linux offers the same experience for a much smaller price tag!

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